Pyrrolidone is particularly useful as an intermediate in the preparation of Nylon-4, in the preparation of N-methyl pyrrolidone and N-vinyl pyrrolidone which is useful as organic solvents, and in the formation of polymers which have certain specific properties.
Pyrrolidone has been prepared according to U.S. Pat. No. 3,095,423 in a liquid phase process comprising the simultaneous hydrogenation and hydrolysis of succinonitrile utilizing aqueous ammonia and hydrogen pressures of at least 500 psi, and preferably hydrogen pressures of from 1000-2000 psi. U.S. Pat. No. 3,781,298 also describes a single step process for preparing 2-pyrrolidone by hydrogenating succinonitrile in an aqueous solution but at pressures greater than 2000 psig. U.S. Pat. No. 3,644,402 discloses a two-step process for hydrolyzing and hydrogenating succinonitrile sequentially, wherein the hydrolysis reaction if conducted in aqueous ammonia and the hydrogenation in the presence of a nitrogen-containing basic organic solvent at pressures of from about 750 to 3000 psi.